Shelves are bare and signs are posted where Blue Bell products were displayed in a grocery store in Overland Park, Kan., on Tuesday. Texas-based Blue Bell Creameries has recalled all products after listeria contamination.

WASHINGTON — The government is relying on some new technology — as well as a bit of luck — to track an outbreak of life-threatening listeria linked to Blue Bell ice cream products.

Texas-based Blue Bell Creameries recalled all its products this week after listeria was found in a variety of the company’s frozen treats. The massive recall followed several smaller recalls as health officials across the country have rapidly worked to track the outbreak, which is so far linked to 10 listeria illnesses, including three deaths.

The investigation has been helped by new technology called whole genome sequencing, which maps all of an organism’s DNA. With help from that new technique, federal and state officials realized the outbreak was not just a recent event — the ice cream had likely made people sick since 2010.

It gives officials hope that future outbreaks can be tracked faster and more accurately. “It is giving us a new power to investigate cold cases,” Dr. Robert Tauxe of the Centers for Disease Control and Prevention said of the genome sequencing.

The first indication of listeria contamination in Blue Bell products came in January, when the South Carolina Department of Health and Environmental Control collected samples from a Blue Bell distribution plant as part of a random-sampling program. The South Carolina officials had no reason to suspect the ice cream was contaminated but unexpectedly found that two of Blue Bell’s products contained high amounts of listeria.

South Carolina notified the Food and Drug Administration, setting off a chain of events that ended with Monday’s massive recall:

• In testing prompted by the South Carolina discovery, the Texas Department of State Health Services found listeria in product samples from the Brenham, Texas, plant where the tainted ice cream was manufactured. Ice cream produced on that line was recalled.

• Samples of listeria matched the strains in patients who contracted listeria after eating Blue Bell ice cream in a Kansas hospital. Three of those patients had died. Further testing by Kansas health officials found listeria in products from a separate Blue Bell plant in Oklahoma, leading to another recall.

• More testing by the FDA and Blue Bell itself led to more recalls and, finally, Monday’s total shutdown of the company’s three manufacturing plants.

Along the way, federal officials were able to track the samples to 10 illnesses going back five years — something they wouldn’t have been able to confirm before they started using the whole genome sequencing in 2013.

It’s still unclear what was happening in the Blue Bell plants or how the listeria got there.

Blue Bell says it is expanding its cleaning and sanitization system, beefing up its employee training, expanding its swabbing system by 800 percent to include more surfaces and sending daily samples to a microbiology laboratory for testing.

The 108-year-old company said it will also test all products produced at its facilities before sending them out to retailers.

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